Hollow body.



E. McGRUER, JR. HOLLOW BODY.

APPLICATION FILED MAR. 25. I916.

I. Patented May 21, 1918.

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EWING MOGRUER, JR., 0F BRAESIDE, CLYNDER, SCOTLAND.

HOLLOW BODY.

To all whom it may concern:

Be it known that T, EWING MoGno-nn, Junior, a subject of the King ofGreat Britain, residing at Braeside, Clynder, Dumbartonshire, Scotland,have invented new and useful Improvements in Hollow Bodies, of which thefollowing is a specification.

This invention relates to improvements in connection with hollow masts,spars, struts, oar shanks and like hollow bodies of wood.

According to this inventiqn a board is quartered-sawed in the directionof the grain and wetted on one-side and heated on the other so that thefibers stretch and contract transversely in any ratio up to 40% of theiroriginal breadth and so allow the board to be bent on the neutral axisof its transverse section.

The drawings show hollow bodies made in I surfaces, if desired. It maybe pointed out that the end grain or natural annual grain rings of theboard a lie toward the opposite hand td that of the board b.

The body shown in Fig. 3- similarly is made of two boards 0 and 03'provided with lap joints 0 and d in a line with one another, the edgesand sides of the boards being glued or cemented together at the joints.As before the grain of the board 0 lies toward the opposite hand to thatof the board d. Preferably the grain of the boards 0 and d is at anangle of 45 to the board at the bends and J When it is desired that thebody be adapted to be used for aeroplane work the body would be madetapered and curved.

The boards before being bent are wetted on one sideand heated at theother as above described. .Otne method is to place a board Specificationof Letters Patent.

' Patented May 2i, rare.

Application filed March 25, 1916. Serial No. 86,576.

to the other side of the board. In this mannor the fibers are contractedon the heated side and stretched on the wetted side.

It is desired that care be taken that 110' destruction of the fibrouscells of the wood takes place.

What I claim is l. A hollow wooden body having the grain of the woodextending longitudlnally thereof, consisting of a plurality of boardsbent and fitted one within the other, the natural grain rings of oneboard lying right-hand, and the natural grain rings of the adjacentboard lying left-hand.

2. A hollow wooden body consisting oftwo or more quarter-sawed boardsbent and fitted one within the other, the end grainof one board lying riht-hand, and the end grain of the adjacent oard lying left-hand.

3. A hollow strut for aeroplanes and the like, comprising aquarter-sawed board hav-- ing its edges cut at an angle and bent to forma curved edge adjacent the central line of the board and an acute anglebetween the sides adjacent the meeting edges.

4. A hollow strut for aeroplanes and the like, comprising a plurality ofquarter sawed boards having their edges out at an angle andv each bentto form a curved edge ad- I jacent the central line thereof and an acuteangle between the sides adjacent the meet-- ing edges, fitted one withinthe other.

5. A hollow strut for aeroplanes and the like, comprising a plurality ofquartersawed boards having their edges cut at an angle and each bent toform a curved edge adjacent the central line of the board and an acuteangle between the sides adjacent the meeting edges, fitted one withinthe other with the end ain of one of the boards extending in t eopposite direction to that of the adjacent boards.

6. The process of forming a hollow body, which consists in' producing aquartersawed board having the end grain extending at an angle ofsubstantially 45 degrees to the sides'of the board, bending the same tocause the edges to abut, and securing the abutting edges. 7. The processof forming a hollow body. which consists in producing a plurality ofquarter-sawed boards each having the end grain extendin at an angle ofsubstantially 45 degrees to t e sides thereof, bending the 45 degrees tot e sides thereof, bending thesame to cause the edges to abut, securingthe abutting edges, and then fitting the boards one within the other.

8. The process of forming a hollow body which consists in producing aplurality oi quarter-sawed boards each having the end grain extendin atan angle of substantially same to cause the edges toabut, securing theabutting edges, and then fitting the boards one within the other withthe end grain of one board extending in the opposite direction to thatin the adjacent board.

9. The process of forming a hollow body, which consists in producing aplurality of quarter-sawed boards each having the end grain extendin atan angle of substantially 45 degrees to t e sides thereof, bending thesame to cause the edges to abut, securing the abutting edges, and thenfitting the boards one within the other with the end grain of one boardextending in the opposite direction to that in the adjacent board, thejoint formed by the abutting edges of one board being circumferentiallydisplaced relatively to that in the adjacent boards.

10. The process of forming a hollow body which consists in producing aplurality oi quarter-sawed boards each having the end grain extending atan angle of substantially 45 degrees to the sides thereof, bending thesame to cause the edges to abut, securing the abutting edges, and thenfitting the boards one within the other with the end grain of one boardextending in the opposite direction to that in the adjacent board,whereby a line extending radially from the longitudinal axis of the bodyintersects a plurality of natural rain rin s.

EWI G MoG UER, JR.

